From: Daniel Vetter <daniel@ffwll.ch>
To: Chris Wilson <chris@chris-wilson.co.uk>,
Namrta Salonie <namrta.salonie@intel.com>,
intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH] drm/i915: Enabling RC6 immediately during init/resume
Date: Tue, 25 Aug 2015 16:32:05 +0200 [thread overview]
Message-ID: <20150825143205.GJ20434@phenom.ffwll.local> (raw)
In-Reply-To: <20150821124126.GV8742@nuc-i3427.alporthouse.com>
On Fri, Aug 21, 2015 at 01:41:26PM +0100, Chris Wilson wrote:
> On Sat, Aug 22, 2015 at 02:19:48AM +0530, Namrta Salonie wrote:
> > Since RC6 enabling does not involve PCU communication overhead,
> > it can be enabled immediately during the resume time.
> > This will help save additional power & meet power requirements
> > for active Idle KPI where power is evaluated over
> > number of transitions of suspend/resume.
> >
> > Signed-off-by: Namrta Salonie <namrta.salonie@intel.com>
> > Signed-off-by: Sagar Arun Kamble <sagar.a.kamble@intel.com>
>
> You can pull out gen9 rc6 as well, and apply a similar transformation to
> gen6-8. So instead of putting the if-chain in
> intel_enable_gt_powersave(), add intel_enable_rc6() and start placing
> the ready functions there.
>
> Reviewing the comments we only need the rpm lock until after rc6
> enabling and as you keep that wakelock, you are not getting the full
> improvement you seek. If you keep refactoring the remaining two rc6
> functions, you can then drop the wakelock.
Since this seems to not have much of a benefit due to the missing removal
of the wakelock I wonder how this was tested ... Next patch should have
(relative, we're not allowed to publish absolute) performance data
attached, e.g. "Over 100 suspend/resume cycles with 5s of idle time in
between each suspend/resume time this reduce in a reduction of $number
$unit."
Without this this patch is just unjustified tuning and I won't take it.
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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next prev parent reply other threads:[~2015-08-25 14:32 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-21 20:49 [PATCH] drm/i915: Enabling RC6 immediately during init/resume Namrta Salonie
2015-08-21 12:41 ` Chris Wilson
2015-08-25 14:32 ` Daniel Vetter [this message]
2015-08-31 11:38 ` Salonie, Namrta
2015-09-02 8:30 ` Daniel Vetter
2015-12-02 5:45 ` Namrta Salonie
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